New data on non-traditional types of East Kazakhstan rare metal ore

This study investigates the trace-element geochemistry of rare-metal pegmatites from the Kalba–Narym Batholith, Eastern Kazakhstan, to establish geochemical indicators of zonation and subtype differentiation within pegmatite fields. Detailed ICP-MS analyses of muscovite and K-feldspar reveal systematic variations in Li, Cs, Rb, Ta, Nb, P, and Ga contents that reflect progressive melt fractionation during the evolution of granitic magmas. These data allow the identification of four main pegmatite subtypes, including barren, beryl, albite–spodumene, and albite, representing successive stages of LCT (Li-Cs-Ta) pegmatite evolution. Both vertical and lateral geochemical zonation are recognized across the Kalba–Narym Batholith, controlled by magmatic differentiation and volatile enrichment. The results highlight the diagnostic value of trace-element systematics in rock-forming minerals as reliable indicators of fractionation and ore potential, and they provide quantitative criteria for the classification and exploration of rare-metal pegmatites within the Kalba–Narym Batholith.

Porphyry copper deposits are one of the main sources of copper in the world and are usually associated with intrusive complexes of calc-alkaline composition formed in subduction-related geodynamic settings. Eastern Kazakhstan is characterized by the presence of a number of large porphyry copper-molybdenum deposits, but the metallogenic potential of many intrusive complexes in the region remains insufficiently studied. This paper presents new geological, mineralogical, and geochemical data on the Bala-Urpek deposit, located within the Sarykol intrusive complex (Eastern Kazakhstan), aimed at identifying diagnostic criteria for porphyry copper mineralization. The present study is based on field geological observations, petrographic analysis, and whole-rock geochemical data obtained by XRF and ICP-MS. Intrusive ore-bearing rocks are mainly represented by granitoids of the calc-alkaline series with I-type geochemical characteristics. Mineralogical studies have revealed veinlet-disseminated sulphide mineralisation, represented mainly by chalcopyrite and pyrite, as well as the development of hydrothermal alteration associations typical of porphyry systems. The geochemical characteristics of the rocks, including enrichment with large-ion lithophile elements and depletion with high-charge elements, indicate the subduction nature of magmatism. The combination of the data obtained allows us to identify geological, mineralogical and geochemical criteria characteristic of copper-porphyry systems and indicates the potential of the Bala-Urpek deposit area and the associated apophyses of the Sarykol complex for further exploration and prospecting.

Қалба кешенінің (Р1) сирек металды минералдану ерекшеліктері қаралып, негізгі пегматит кен алаңдары мен қалба кешенінің I фазасының гранитоидтары арасындағы генетикалық байланыс анықталды. Қалба-Нарым аймағында бірнеше кенді аймақтар ерекшеленеді. Негізгі сирек металды кен аймағы Орталық Қалбамен шектеседі. Мұнда зерттелген сирек металды (Ta, Nb, Be, Li, Sn) пегматит нысандары – Огнев-Бакенді және Асу-Бұлақ кен алаңдары шоғырланған. Солтүстік-Батыс Қалбада Кварцты кен орны және берилл-сподумен минералдануымен сипатталатын бірқатар кенбілінімдер орналасқан. Мұндағы кен орындары мен кенбілінімдері қалба кешенінің II фазасының гранитоидтарымен байланысты болады. Бұл кен орындарының барлығы заманауи геофизикалық әдістер мен жоғары дәлдіктегі геохимияны қолдана отырып, толық зерттеуді қажет етед The features of rare-metal mineralisation of the Kalba complex (P1) are considered, the genetic connection between granitoids of the I phase of the Kalba complex and the main pegmatite ore fields is established. Several ore zones are distinguished within the Kalba-Narym zone. The main rare-metal ore zone is confined to the Central Kalba. The most studied rare-metal (Ta, Nb, Be, Li, Sn) pegmatite objects – the Ognevsko-Bakennoe and Asu-Bulak ore fields – are concentrated here. In North-Western Kalba there is the Kvartsevoye deposit and a number of ore occurrences characterised by beryl-spodumene mineralisation. Deposits and occurrences here are confined to granitoids of phase II of the Kalba complex. All these deposits require further exploration using modern geophysical methods and high-precision geochemistry Рассмотрены особенности редкометалльной минерализации калбинского комплекса (Р1), установлена генетическая связь между гранитоидами I фазы калбинского комплекса и основными пегматитовыми рудными полями. В пределах Калба-Нарымской зоны выделяется несколько рудных зон. Основная редкометалльная рудная зона приурочена к Центральной Калбе. Здесь сосредоточены наиболее изученные редкометалльные (Ta, Nb, Be, Li, Sn) пегматитовые объекты – Огневско-Бакенное и Асу-Булакское рудные поля. В Северо-Западной Калбе расположено месторождение Кварцевое и ряд рудопроявлений, харак- теризующиеся берилл-сподуменовой минерализацией. Месторождения и проявления здесь приурочены в гранитоидам II фазы калбинского комплекса. Все эти месторождения требуют доизучения с использованием современных геофизических методов и высокоточной геохимии Калба-Нарымская зона, калбинский комплекс, фаза, граниты, пегматиты, редкие элементы

Rare-metal pegmatites of the Kalba–Narym belt (Eastern Kazakhstan) represent an important source of Li, Cs, Ta, Nb, Be, and associated critical metals. Despite extensive geological investigations, the relationships between granites, pegmatites, and late-stage alteration products within the Central Kalba ore district remain insufficiently constrained. This study integrates whole-rock geochemistry and muscovite trace-element data to evaluate regional fractionation trends and rare-metal enrichment within the granite–pegmatite system. The dataset comprises 29 whole-rock samples, including Phase I and Phase II granites, pegmatites, greisens, and hornfels, together with 11 muscovite separates from the Akhmetkino, Yubileynoye, Bakennoye, and Asubulak ore fields. Geochemical evolution was assessed using granite-normalized multi-element patterns and the Cs–Rb, K/Rb–Cs, Li–Rb, Li–Cs, Rb/Sr–Cs, and Ta–Cs relationships. Muscovite compositions were additionally compared with published datasets from the Totoral (Argentina) and Gatumba (Rwanda) pegmatite districts. The results reveal systematic enrichment in Li, Rb, Cs, Nb, and Ta accompanied by depletion in Sr and Ba from granites to the most evolved pegmatites. The strongest geochemical relationship is recorded by the Rb/Sr–Cs system (R² = 0.805), whereas Ta and Cs show only weak correlation (R² = 0.062). Muscovite compositions display decreasing K/Rb and K/Cs ratios and increasing Rb and Cs concentrations from Akhmetkino through Yubileynoye and Bakennoye to Asubulak, defining a regional fractionation sequence consistent with whole-rock geochemistry. The most evolved muscovites overlap compositional fields characteristic of highly fractionated LCT pegmatites. The geochemical patterns identified in both whole-rock and muscovite datasets indicate progressive melt evolution across the Central Kalba district. Late-stage alteration and volatile-rich mineral assemblages record additional fluid-related processes, although their quantitative contribution to rare-metal redistribution remains uncertain. The results identify Cs, Rb/Sr, K/Rb, and K/Cs as useful indicators of relative pegmatite evolution and provide new constraints on the development of rare-metal granite–pegmatite systems in Eastern Kazakhstan.